Batteries

The batteries and in case of not having Linux, the operating
system are having the most impact to the price of a Netbook.
The low cost Acer Aspire One ZG5 came with a 10.8V 2200mAh
standard capacity battery pack, no Windows and no hard disk.
The battery does not last for a whole day business trip.
Luckily there are other sizes available, but not at a very low
price:

A closer look shows that the batteries used are smart
batteries that have a complex electronics inside that can be
read via SMBus:

cat
/proc/acpi/battery/BAT1/info

cat
/proc/acpi/battery/BAT1/state

The AAO has an SMBus Level 2 Battery Charger from Intersil
ISL88731. Battery level 2 charger do initiate any charge on
their own, they wait until the smart battery requests to get
charged. Additionally there is also the Embedded Controller
WPCE775 from Nuvotron that has two SmBus connections, where the
first is connected to the battery and the second to the other
I2C devices on the motherboard. Unfortunately Linux seems to
have just access to the 2nd I2C bus.

Looking at the battery connector all 5 Smart battery signals
can be found:

An external I2C adapter can be connected to the battery.

Important

Care has to be taken, since I2C does not use always the
same signals. The AAO uses 3V signals but the external I2C
adapter might use 5V signals.

It can happen that the batteries report errors as requesting
a Conditioning Cycle. Usually this is a full charge and full
discharge charge cycle.

There are two fuses on the motherboard one for the external
power adapter (5A) and one for the battery (7A). It can happen
that those fuses blow. Having the AOO unpowered and opened, a
Ohm meter shows quickly if the fuses are blown. Unfortunately
the fuses are SMD components and can not easily replaced.

Alternatively, the following shows a blown fuse and how to
connect a 5*20mm replacement fuse in parallel.